The present invention relates to a wedge for restricting the end play of a free-end of a rotatable shaft, and more particularly, a wedge for restricting the end play of a window lift motor.
Window lift motors for motor vehicles typically have axial end play problems. Currently, screw-type corrections for axial end play are employed in the automotive industry. The screw-type mechanism can be subject to failure due to malformed, deformed, or damaged threads preventing the mechanism from eliminating the axial end play problem. The screw-type correction mechanism requires significant cost to form the multiple parts and to form the threads on the interacting components. In addition, the threaded interaction requires preassembly of the components prior to assembly into a final product.
The present invention provides a cost effective and robust solution to the window lift motor axial end play problems. The present invention provides enhanced motor durability and improved cost. The end play restriction wedge according to the present invention provides a female wedge housing in combination with a male wedge for carrying the axial thrust load in compression and requires no threads to operate. Interlocking teeth or serrations on both parts of the wedge retain the male wedge in an assembled position with respect to the female wedge housing. An angled thrust plate is mounted to the female wedge housing and trapped between the armature tip and a gear housing floor to prevent dislodging movement. The present invention provides substantial cost savings due to fewer number of components and by eliminating the need for preassembly of the components by the component supplier. The flexible wedge geometry according to the present invention eliminates tight tolerance dimensional requirements for the end play housing and gear housing pockets resulting in improved assembly compatibility.
The end play restriction wedge according to the present invention is a one piece plastic part with an insert molded metal thrust plate. The invention is intended to be installed inside the window lift actuator plastic gear housing after the armature and the motor housing are assembled. In operation, the male wedge is pushed down by an external force and breaks loose into the female tapered wedge housing. The female wedge housing wedges open to fill the back tapered gear housing pocket and advances forward to eliminate any excessive end play inside the motor assembly. The locking teeth, as well as the interference fit between the female wedge housing and the gear housing pocket, keep the end play assembly from coming loose during motor durability cycles.
Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.